When sitting in the passenger seat the brake bar has to be pushed to the left to activate the brakes. As this is located to the right of the passenger foot wells it would have to be moved with your right foot to the left, but as you wont have the leverage from the brake pedal i find it very hard to belive it can be moved with enough force to lock the wheels.
Your friend must be huge with tiny feet to fit in the small gap.
Your friend must be huge with tiny feet to fit in the small gap.